With the score 30-0 deep in the fifth set a spectator yelled out loudly during Nadal's ball toss, which distracted the Spaniard and forced him to serve a fault.

But in an admirable show of sportsmanship Smyczek called for Nadal to replay his first serve rather than it be declared a fault.

Nadal went on to win the epic match and take his place in the third round at the Open, while Smyczek bowed out.

Smyczek's graceful act in the dog-eat-dog world of professional tennis was a major talking point at the Australian Open on Thursday.

"Very few players can do that after four hours something of a match, 5-all, love-30. So I just will say thanks to him because he's a great example what he did," Nadal said.

"He's a gentleman. Not a lot of people would do something like that."

World number one Djokovic was similarly effusive about Smyczek's sporting act towards the Spaniard.

"I've seen the great gentleman gesture and sportsmanship from Smyczek. I think that's something that people should talk about," he said.

"This is something that is not very common in the sport today, where media and people generally emphasize on the rivalries, feisty, aggressive kind of approach to matches.

"It's nice to have something that is greater than sport itself, the sportsmanship and fair play."

Swiss star Stan Wawrinka, who is defending his Australian Open title, also praised the American.

"I think it was great for him to give back the point. You don't see it so many times and it's great sportsmanship."

Asked if he would have done the same, Wawrinka added: "I don't know. Let's see. You cannot answer that. After four hours of the match you don't know what's in your mind. Sometimes you react just like that. You just do it. Hope so I will do it."

For Smyczek's part, he offered when asked about his gesture: "It clearly bothered him (Nadal). You know, I thought it was the right thing to do.